Installing kubeadm
This page shows how to use install kubeadm.
- Before you begin
- Check required ports
- Installing Docker
- Installing kubectl
- Installing kubelet and kubeadm
- What’s next
Before you begin
- One or more machines running Ubuntu 16.04+, CentOS 7 or HypriotOS v1.0.1+
- 1GB or more of RAM per machine (any less will leave little room for your apps)
- Full network connectivity between all machines in the cluster (public or private network is fine)
- Unique MAC address and product_uuid for every node
- Certain ports are open on your machines. See the section below for more details
Check required ports
Master node(s)
| Port Range | Purpose |
|---|---|
| 6443* | Kubernetes API server |
| 2379-2380 | etcd server client API |
| 10250 | Kubelet API |
| 10251 | kube-scheduler |
| 10252 | kube-controller-manager |
| 10255 | Read-only Kubelet API (Heapster) |
Worker node(s)
| Port Range | Purpose |
|---|---|
| 10250 | Kubelet API |
| 10255 | Read-only Kubelet API (Heapster) |
| 30000-32767 | Default port range for NodePort Services. Typically, these ports would need to be exposed to external load-balancers, or other external consumers of the application itself. |
Any port numbers marked with * are overridable, so you will need to ensure any custom ports you provide are also open.
Although etcd ports are included in master nodes, you can also host your own etcd cluster externally on custom ports.
The pod network plugin you use (see below) may also require certain ports to be open. Since this differs with each pod network plugin, please see the documentation for the plugins about what port(s) those need.
Installing Docker
On each of your machines, install Docker. Version 1.12 is recommended, but v1.10 and v1.11 are known to work as well. Versions 1.13 and 17.03+ have not yet been tested and verified by the Kubernetes node team. For installation instructions, see Install Docker.
Installing kubectl
On each of your machines, install kubectl. You only need kubectl on the master and/or your workstation, but it can be useful to have on the other nodes as well.
Installing kubelet and kubeadm
You will install these packages on all of your machines:
-
kubelet: the component that runs on all of the machines in your cluster and does things like starting pods and containers. -
kubeadm: the command to bootstrap the cluster.
Note: If you already have kubeadm installed, you should do a apt-get update &&
apt-get upgrade or yum update to get the latest version of kubeadm. See the
kubeadm release notes if you want to read about the different kubeadm
releases.
For each machine:
-
SSH into the machine and become root if you are not already (for example, run
sudo -i). -
If the machine is running Ubuntu or HypriotOS, run:
apt-get update && apt-get install -y apt-transport-https curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - cat <<EOF >/etc/apt/sources.list.d/kubernetes.list deb http://apt.kubernetes.io/ kubernetes-xenial main EOF apt-get update apt-get install -y kubelet kubeadm -
If the machine is running CentOS, run:
cat <<EOF > /etc/yum.repos.d/kubernetes.repo [kubernetes] name=Kubernetes baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64 enabled=1 gpgcheck=1 repo_gpgcheck=1 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg EOF setenforce 0 yum install -y kubelet kubeadm systemctl enable kubelet && systemctl start kubelet
The kubelet is now restarting every few seconds, as it waits in a crashloop for kubeadm to tell it what to do.
Note: Disabling SELinux by running setenforce 0 is required to allow
containers to access the host filesystem, which is required by pod networks for
example. You have to do this until SELinux support is improved in the kubelet.